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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
G. C. Pomraning
Nuclear Science and Engineering | Volume 21 | Number 1 | January 1965 | Pages 62-78
Technical Paper | doi.org/10.13182/NSE65-A21016
Articles are hosted by Taylor and Francis Online.
A diffusion theory for the asymptotic transport scalar flux is derived from the monoenergetic transport equation in slab geometry. By allowing the scalar flux to be discontinuous at a material property and/or an external-source discontinuity, the theory is able to predict exact asymptotic transport-theory behavior for two standard halfspace problems. A supplementary diffusion-like theory is developed to treat the non-asymptotic flux. The total (asymptotic plus non-asymptotic) formalism yields a continuous scalar flux distribution and gives exact transport -theory leakage from a halfspace with a spatially-constant source. Numerous numerical comparisons indicate that the theory proposed here is significantly more accurate than classical (P1) diffusion theory. The complexity of both the asymptotic and non-asymptotic formalisms is comparable with that of the P1 method. Finally, the entire formalism is generalized to three dimensions in rectilinear- and curvilinear-coordinate systems.
